1. Field of the Invention
This invention relates to raw material charging apparatus at the top of the furnace, especially of the bell-less type having a rotating chute.
2. Description of the Prior Art
The raw material charging apparatus of the bell-less type are known which employ a chute in association with rotation and tilting for optional charging distribution in place of the large bell.
A conventional charging apparatus of this bell-less type will be discussed with reference to FIG. 1 of the attached drawings. The apparatus comprises bunkers 7, 8 which are alternately charged with raw materials by means of switching chutes provided with exhaust ports 65, 66 having raw material control gates 63, 64; a collecting chute 6a arranged under the exhaust ports 65, 66: a rotating drive chamber positioned under the collecting chute 6a via an elastic pipe 5; a vertical chute 4 which can be extracted upwardly is inserted in the rotating drive chamber 3; a rotating distribution chute 2, is provided under the vertical chute 4, which is movable up and down; and swingable sealing valves 67, 68 are furnished in the collecting chute 6a at parts thereof corresponding to the exhausting ports 65, 66 of the bunkers 7, 8 for avoiding leakage of gas during the charging operation. Thus, the raw materials are filled into either of the bunkers 7, 8, and passed through the collecting chute 6a, the vertical chute 4 and the rotary chute 2, and thrown into the furnace.
For fixedly securing the bunkers 7, 8 and the collecting chute 6a, upright beams 40, 41 stand from parts of the furnace 1 near the rotating driver 3, which terminate in height about the center of the collecting chute, and securing beams 42, 43 are placed on said terminations of the beams 40, 41 between which a box beam 44 is bridged thereover. In such ways, the bunkers 7, 8 are secured on the box beam 44, and the collecting chute 6a is supported through a horizontal supporting member 45.
In this type of the raw material charging apparatus, since the vertical chute is subject to extreme wear and the rotating drive chamber is easily subjected to abnormality owing to the functions and the charging operations, they are often taken out of the furnace for periodic inspection and also due to breakdowns. It is the general routine that the collecting chute 6a is taken away, and the vertical chute 4 and the rotating drive chamber 3 are removed. The collecting chute 6a can be easily removed, but because of the longitudinally and laterally positioned box beam 44, securing beams 42, 43 and upright beams 40, 41, only a limited narrow space remains. Further, the rotating drive chamber 3 which is very heavy (in general more than 30 tons) and the vertical chute 4 are removed by a winch, or the like, while care must be taken to prevent these components from colliding against the vertical beams 40, 41 or the securing beams 42, 43, and therefore, because of the many steps involved and a great deal of time and labor, expense and down time are required for repair.